In downhole industries such as hydrocarbon exploration and recovery, Carbon Dioxide sequestration, etc., it is often valuable for an operator to measure various formation and or fluid parameters. Such tools are commonly run on wireline but can be conveyed on any string. In one example, fluid mobility in the formation is tested by withdrawing a volume of fluid therefrom through a probe and analyzing drawdown pressures to determine the mobility of that fluid. Equations used by the industry are common and standard and are configured to address variables that are encountered. This unfortunately makes output information good but not optimum since variables inject a measure of uncertainty into the mix.
Many different formation testing tools have been used for such endeavors through the years and in general they work well for their intended purposes. Many however are also quite complex and relatively expensive to construct. They are also reliant upon positive hydraulic fluid pressure to extend and to retract thereby necessitating ported hydraulic fluid to different chambers of a piston system. Some of the complexity and engineering requirements of prior tools are driven by these considerations. Further, due to complexity, there are often multiple failure opportunities that require frequent maintenance and may cause downtime for operating tools.
Due to the above mentioned drawbacks of existing tools, the art is always receptive to improvements in such tools.